A century of urban planning decisions has resulted in lifestyles where we spend too much time commuting alone in cars and too little time being active, too little time outdoors, and too little time interacting with people face-to-face, in our homes or just serendipitously on the sidewalk. The choices made as we design and build urban environments have a profound impact not only on how we live, but on how well we live — and how healthy we are.